Soil/Landform Unit - Glenorchy rises

Glenorchy rises looking north-west towards Dadswells Bridge with the Wimmera River in the north

Area: 24 918 ha

1.06% of CMA region

Gentle rises south-east of Glenorchy constitute part of the

landscapes of the Dissected Western Uplands (2.1.5). Derived mainly of Parilla Sand, the rises are divided into landforms with parent material sourced from

in situ

Parilla Sand with the more prominent rises having deeply weathered

regolith

profiles that include significant kaolinitic development under Cainozoic deposits. Plains, rises and drainage depressions are the major landform components with soils including

sodic

and non-sodic, red, yellow and brown texture contrast soils (

Chromosols

and

Sodosols

) and red gradational or uniform soils (

Dermosols

) dominant.

Hardsetting

and soft surfaces are susceptible to sheet and rill erosion even on gentle slopes due to impeding layers such as hardpans or massive clay subsoils. Gully erosion occurs where sodic subsoils are exposed while topsoils may be susceptible to

acidification

. Dryland cereal cropping along with sheep grazing are major land uses. Vegetation communities range from Heathy Woodland to Box Ironbark Forest and Plains Sedgy Woodland.

Stiking mottling found within subsoils of the sedimentary rises
	Greens Swamps at Greens Creek

Component	1	2	3	4
Proportion of soil-landform unit	3%	55%	32%	10%
CLIMATE Rainfall (mm)	Annual: 540
CLIMATE Rainfall (mm)	Annual: 540
Temperature (^oC)	Minimum 8, Maximum 20
Precipitation less than potential evapotranspiration	October–April
GEOLOGY Age and lithology	Quaternary fluvial silt, sand, minor gravel (Shepparton Formation); Neogene fluvial silt, sand, minor gravel; Cambrian marine sandstone, siltstone, biotite schist (St Arnaud Group); Cambrian ‘greenstone’ – basalt, andesite, boninite, rhyolite, gabbro, lithic sandstone, chert, shale and breccia
GEOLOGY Age and lithology
Geomorphology	2.1.5 Cainozoic landscapes of the Dissected Western Uplands
LANDUSE	Uncleared areas: water supply; nature conservation Cleared areas: heep and beef cattle grazing; dryland cropping; water supply
LANDUSE
TOPOGRAPHY Landscape	Dissected plain
TOPOGRAPHY Landscape	Dissected plain
Elevation range (m)	159–282
Local relief (m)	20
Drainage pattern	Dendritic
Drainage density (km/km²)	0.6
Landform	Rises (Glenorchy 2)		Plains (Glenorchy 1)
Landform element	Drainage depression	Rise	Plain	Drainage depression
Slope and range (%)	3 (1-7)	5 (3-10)	2 (1-5)	1 (0-2)
Slope shape	Concave	Convex	Straight	Concave
NATIVE VEGETATION Ecological Vegetation Class	Plains Grassy Woodland (37.1%), Plains Woodland (19.6%), Heathy Woodland (13.2%), Grassy Woodland (6.6%), Other (22.1%)
NATIVE VEGETATION Ecological Vegetation Class
SOIL Parent material	Alluvial sand, silt and minor gravel	Marine sandstone, siltstone and biotite schist, minor greenstone	Marine and fluvial silt, sand and gravel	Alluvial gravel, sand and silt
SOIL Parent material	Alluvial sand, silt and minor gravel		Marine and fluvial silt, sand and gravel	Alluvial gravel, sand and silt
Description (Corangamite Soil Group)	Sodic and non-sodic, yellow and brown texture contrast soils (5)	Sodic and non-sodic, brown and red texture contrast soils (6) red gradational or uniform soils (7)	Sodic and non-sodic, yellow and brown texture contrast soils (5) and sodic and non-sodic, brown and red texture contrast soils (6)	Sodic and non-sodic, yellow and brown texture contrast soils (5)
Soil type sites	DOAGW15	WLRA141, WLRA142, WLRA138	DOAGW15, WLRA141, WLRA142	DOAGW15
Surface texture	Sandy clay loam	Silty loam	Sandy clay loam	Sandy clay loam
Permeability	Moderate	Moderate to high	Moderate	Moderate
Depth (m)	> 2	1.5	2	> 2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS Critical land features, processes, forms	Hardsetting and soft surfaces susceptible to sheet and rill erosion even on gentle slopes due to impeding layer (clay or hardpan). Subsurface soil and upper subsoil susceptible to compaction, and also gully erosion where sodic and deep. Topsoil may be susceptible to acidification.	Gradational gravelly soils are well drained, steeper slopes with hardsetting and soft surfaces are susceptible to sheet and rill erosion (especially lighter surface soil). Upper soil susceptible to increased acidification	Hardsetting and soft surfaces susceptible to sheet and rill erosion even on gentle slope due to impeding layer (clay or hardpan). Subsurface soil and upper subsoil susceptible to compaction. Gully erosion occurs where sodic subsoils are exposed. Topsoil may be susceptible to acidification.	Hardsetting and soft surfaces susceptible to sheet and rill erosion even on gentle slope due to impeding layer (clay or hardpan). Subsurface soil and upper subsoil susceptible to compaction, and also gully erosion where sodic and deep. Topsoil may be susceptible to acidification.

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